George Miles posted
I have several emergency lights over the stairs etc, which light up
when the mains fails.

But if they only last 4 hours, and the power trips when i'm asleep at
midnight,

.... and if the emergency lights all coming on doesn't wake anybody up,
and if nobody who wakes up during the night notices that the emergency
lights have come on ...

and fire breaks out at 6 a.m. or i need to get up,

Eh?

they will be flat.

So recommendations for emergency lights with longer lasting batteries please?

If you're going to be that unlucky, you might as well not bother with
emergency lights in the first place.

--
Algernon